The present invention relates to a method and an apparatus for folding an airbag.
Vehicle airbags are found in most automobiles and in the event of a collision, they are inflated by gas originating from an inflator. The vehicle airbags together with the inflators are mounted in a vehicle as part of the airbag module. The airbags are usually arranged in the airbag module in a folded state and must be folded in such a way that it can unfold as quickly as possible in a specific direction.
Airbags are conventionally folded by spreading the airbag cushion out flat and then folding it specifically at predetermined points resulting in a folded arrangement. This folded arrangement can be accomplished manually, by an automated machine, or both.
There are several disadvantages to the conventional folding method. For example, a very large amount of space is necessary for the purpose of folding the airbag, since the entire airbag must first be spread out flat. Also, the folding process is time consuming since the airbag has to be precisely folded. Furthermore, for automated folding of the airbag, there is a need for a relatively complicated installation, which has to be adapted individually to each case to different airbag shapes and the specific folding sequence thereof. Such complicated folding can only be performed at a limited speed.
U.S. Pat. No. 6,248,052 B1 teaches a method for the folding of an inflatable airbag for motor vehicles which comprises the steps in which an airbag to be folded is fastened with its open end at a carrier. A piston is pushed forward into the airbag through an opening in the carrier and against the closed end of the airbag. The carrier and the piston are introduced into a sleeve, with the airbag being pressed together irregularly.
U.S. application U.S. Pat. No. 6,327,838 B1 teaches a method for folding an airbag for an airbag module involving the straightening out of the airbag, pushing or drawing the airbag into an outer guide device, and lastly pushing the airbag together with the outer device to fold the airbag.
In the present invention, the folding apparatus comprises a plunger mechanism, a folder support apparatus, and a folding tube. The plunger mechanism has a plunger plate, which is attached to an airbag during the folding process. The folder support apparatus has a base reservoir for accommodating the airbag in its folded state. The folding tube has an upper rim defining an opening for receiving an airbag.
The process of folding the airbag consists of the following steps. Attaching a plunger mechanism to an airbag and dropping the airbag into a folding tube. The airbag is compressed into a folder base of the folding tube by forcibly lowering the plunger mechanism down the folding tube, wherein the plunger mechanism remains exterior to the airbag during the folding process. Lastly, the folded airbag is wrapped with a fold retention sheet to prevent it from becoming unfolded.